lilo was removed from the CDs in lucid because grub2 can now deal with all the remaining cases where it was used by default, so the usefulness vs. CD space trade-off no longer made sense (a third of a megabyte is not a huge amount, but it's still valuable real estate). Due to an oversight, lilo-installer was left on the CD. I've removed it now.

Of course, it's still possible to install with lilo using netboot installations, which don't have the same space constraints.